Our gang spends some of the most miserable weather out in their run (they have 24/7 access to the coop and fully enclosed run). We've seen the silly things roost outdoors at night in temperatures down in the single digits.

They'll be fine- least ways mine always are. Just let 'em wander and go back in the coop when they feel the need. It just barely cracked 32 degrees here today and they have wandered the yard all day and I even got the same amount of eggs I usually do.